1. Field of the Invention
The present invention relates generally to online content distribution and, more specifically, to verifying the authenticity of a device.
2. Description of the Related Art
Conventional digital content distribution systems include a content server, an application server, a content player, and a communications network connecting the content server to the content player. The content server is configured to store digital content items corresponding to different content titles that can be downloaded from the content server to the content player. The application server allows a user of the content player to browse through available digital content and manage account information, etc.
Before content can be played within the content player, the authenticity of the device on which the content player executes needs to be verified. Typically, a cryptographic key per device or per device model provided by the device manufacturer is stored in a storage component accessible by the application server and by the device itself. When the content player requests digital content for playback, the application verifies the authenticity of the device by matching a cryptographic proof of possession created by the corresponding key retrieved from the storage component and the key used by the device.
There are two main drawbacks to this approach. First, storing and maintaining a unique a key per device on the application server is extremely inefficient from a key management perspective. Second, in a scenario where multiple devices share the same device model key, if the key of a single device is compromised, i.e., illegally retrieved from the device, then the security of all other devices sharing that key is also compromised. In such a scenario, those devices cannot securely be authenticated.
As the foregoing illustrates, what is needed in the art is a mechanism for verifying the authenticity of the playback device using a simple key management mechanism and without storing the same master cryptographic key on all devices of a given model.